More particularly, the invention relates to an articulation system comprising:                first and second articulations, each comprising two fittings which are pivotable relative to one another and a locking mechanism which comprises at least one control member which is mobile between a locked position and an unlocked position, the locking mechanism being capable of locking the two fittings when the control member is in the locked position and unlocking the two fittings when the control member is in the unlocked position, the control members of the two articulations each being urged in a resilient manner into the locked position by a return member arranged between the fittings,        a manoeuvring member which is mobile in rotation between a neutral position and an actuating position and capable of displacing the control members of the first and second articulations from the locked position to the unlocked position when said manoeuvring member is displaced in a first direction from the rest position into the actuating position.        
The document FR-A-2941180 discloses an example of such a system in which the manoeuvring member comprises a connecting bar which in turn is fixed to the control member of the first articulation and connected with angular clearance to the control member of the second articulation. Said known systems, where one of the articulations is the master and the other the slave, do not permit the locking mechanisms of the two articulations to be completely in the rest position in the absence of the actuation of the manoeuvring member.
More specifically, it may arise that the control member of one of the articulations arrives in the rest position before the other, in which case only one of the articulations is locked, the other articulation remaining unlocked even in the absence of the actuation of the manoeuvring member. Moreover, in the known systems, the manoeuvring member may be damaged in the event of significant force in a direction opposing the actuating direction.